The present invention relates to a process for preparing beads as food or tobacco additive containing at least one active ingredient, to methods of use of the beads and to the beads themselves.
A frequent problem associated with the application of flavor systems in the preparation of food or tobacco products is the loss of flavor by volatilization or chemical decomposition. The harsh environment of some food processes like baking, extruding, retorting and deep firing, to name a few, create unique problems for the survival of flavors in finished food products. The loss of flavor usually results in flavor profile distortion or even in complete loss of flavor. Therefore, food scientists and application specialists are continuously searching for methods to protect flavors against volatilization and decomposition during processing.
Another category of flavor application problems results from differences in the interaction between the flavor compounds and the product base. These differences in the flavor-matrix interactions result also in flavor distortion due to the different rates of flavor release during consumption of the product. Typical examples of this type of flavor application problems are the change of flavor character and strength in chewing gum during mastication and the flavor imbalance observed when applying standard flavors to low fat products.
One of the preferred methods to control flavor retention and release is encapsulation. A considerable amount of effort has been devoted for many years to provide solid particulate flavoring materials in which a flavor is contained in the particulate matrix. Various attempts have been made to fix the flavors in many different types of organic matrices to provide stable free-flowing powders of particles which contain the flavor for flavor release when incorporated in foods. Several principle technologies have been proposed for the preparation of solid particulate flavoring materials.
The first category of encapsulated flavors consists of water-soluble particles containing a dispersion of flavor oil. A number of water-soluble carrier materials are employed in the production of this type of encapsulated flavors, such as sugars, modified starches and gums. The industry commonly utilizes spray drying, extrusion and fluidized bed coating to produce the particles. Flavors encapsulated in a water-soluble matrix can be used for controlling flavor delivery and improving flavor stability in dry products such as chewing gum, pressed tablets and dry mixes for the preparation of instant soups, beverages, sauces and desserts. However, this type of encapsulation is unsuitable for improving flavor performance in products that contain water because of dissolution of the particulate flavoring materials. Since in the preparation of most foods, water is involved at any stage of the processing, encapsulation in water-soluble matrices has limited applicability for improving flavor stability or for controlling flavor retention and release.
To overcome the problem of dissolution of the capsule matrix during processing in moist environment, fat encapsulation is sometimes being used (second category). However, the use of fat encapsulated flavors is limited to food products that are processed at relatively low temperatures, because at temperatures above the melting point of the fat much of the effectiveness of the encapsulation is lost. In practice, this means that fat encapsulation can not effectively be used for controlled flavor delivery in products that are heated above 80.degree. C. which comprises the majority of products that is boiled, baked, roasted, (deep) fried or extruded.
The third category of encapsulated flavors consists of particles that are water-insoluble and heat-stable. The methods currently being used to prepare such particles are micro-encapsulation by coacervation and encapsulation in microorganisms.
The encapsulation of flavor oils in heat-stable water-insoluble coacervation microcapsules is described in the patent applications WO 93/19621 and WO 93/19622. The encapsulation of flavor oils in microorganisms is described in European patent application 242,135; the application of microbial cells for controlled flavor release from chewing gum is described in European patent application 528 466.
Both microbial cells and coacervation microcapsules are able to survive food processes like baking, extruding, retorting and deep frying. The major risk for this type of capsules is that they are ruptured during the process as a consequence of the shear forces applied during mixing, grinding or other high-shear processes to which the product is subjected during its production. Therefore, it would be advantageous to have microencapsulated flavors that are less sensitive to shear.
Other potentially interesting materials for the preparation of heat stable, water-insoluble flavor microparticles are salts of anionic polysaccharides such as the calcium salts of alginic acid, pectin and gellan gum. Calcium alginate, in particular, has found useful application as a water-insoluble matrix for the encapsulation of microbial cells (T. Shiotani and T. Yamane, Eur. J. Appl. Microbiol. Biotechnol. 13 (2) 96-101 [1981]; H. C. Provost, Divies and T. Rousseau, Biotechnol. Lett. 7 (4) 247-52 [19851]), enzymes (P. Brodelius and K. Mosbach, Adv. Appl. Microbiol., 28,1 [1982]), drugs (H. Tomida, C. Mizuo, C. Nakamura and S. Kiryu, Chem. Pharm. Bull. 41 (12) 2161-2165 [1993]), vitamins (U.S. Pat. No. 4,389,419), colorings (K. Saito, T. Mori and K. -I. Miyamoto, Food Chem. 50, 311-312 [1994]), foods and food ingedients (U.S. Pat. Nos. 4,507,327; 4,702,921; 5,456,937), cosmetics (European patent application 391,803), and herbicides (A.B. Pepperman, J. C. W. Kuan and McCombs, J. Controlled Release 17, 105 [1991]). However, for the encapsulation of flavors, calcium alginate or other heat stable polysaccharides have hardly been used. This is not surprising in view of the poor barrier properties of these gels for flavor compounds.
The encapsulation of flavors in aqueous gellan gum gel beads has been described in U.S. Pat. No. 5,456,937. The flavors were encapsulated to provide a product for direct incorporation into dry mixes and juices were prepared therewith without the objective of controlling flavor release.
The use of alginate for controlled flavor delivery is described in European patent application 221,850. This describes the use of calcium alginate for the controlled delivery of water-insoluble flavors from chewing gum. The process for encapsulation involves separation of the alginate matrix from a large excess of water followed by air drying. Therefore, this process is not suitable for encapsulation of water-soluble and volatile flavors, because these compounds either remain in the aqueous phase or volatilize during drying. Moreover, the approach does not allow control of flavor release by variation of particle size, porosity and flavor solvent composition.
While the above methods for the preparation for heat-stable, water-insoluble capsules allows improvement of flavor retention under harsh conditions, there are restrictions that limit the wide use of these technologies. For example, the existing methods do not allow the encapsulation of water-soluble and volatile flavors with high efficiency. With the available methods, these flavor components are either lost with removal of the water phase (water soluble compounds) or during the drying step (volatile compounds). Moreover, these methods, in particular, coacervation and absorption into microorganisms, are not suitable for encapsulating solid flavoring materials. And finally, these capsules can not withstand high shear conditions which is often required to reduce the risk of premature release by capsule breakage.
In the copending European patent application number 96 20 2823 a method for the production and use of flavors and other active ingredients encapsulated in dry water-insoluble, heat stable gel beads have been described. However, use of this method requires that the active ingredient is oil soluble. It would be advantageous to have also an encapsulation method that allows the encapsulation of oil insoluble active ingredients, especially of oil insoluble flavors, either as single ingredient or in combination, e.g. with vegetable oil, an emulsifier, extender, filler material or adsorbent, providing beads as food or tobacco additive which beads improve retention and stability of the active ingredients during processing and storage without adversely affecting their release during consumption of the food or tobacco product. An object of the invention is to fulfill this demand.